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JSON Validator
Check strict JSON syntax, Unicode, duplicate keys, and supported structure bounds.
JSON
JSON
Browser only
Your input and output are processed in this browser. They are not uploaded for processing. No account is required.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Paste JSON text or choose a UTF-8 file; a chosen file takes precedence.
- A successful validation also makes a readable JSON download available. Errors do not replace valid content silently.
- Select Process data, review the result, and download it. Use Reset to clear the working data.
Examples
{"name":"Alice","count":9007199254740993,"active":true}
Limitations
5 MiB input; 40 nesting levels; 200,000 values; 20 MiB output. Duplicate keys and unpaired Unicode surrogates are rejected. Numbers retain exact tokens.
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